drm/amdgpu: flag iceland as experimental
drm/amdgpu: flag iceland as experimental

These have not been tested very extensively and generally
seem to be problematic.  Mark them as experimental for now.

bug:
https://bugs.freedesktop.org/show_bug.cgi?id=92270

Reviewed-by: Christian König <c7ea837d7a46effe4232b086213468b8b31643bf@amd.com>
Signed-off-by: Alex Deucher <08dc22c6156113f2deff178e35e3ed9b24d6af9e@amd.com>
Cc: 4fbacc2fa0ffdbb11bf1ad6925b886ebd08dd15f@vger.kernel.org

KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs